From: Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx>
The kvm->srcu lock has to be held while accessing the memory of
guests and during certain other actions. This patch now adds
the locks to the __vcpu_run function so that all affected code
is protected now (and additionally to the KVM_S390_STORE_STATUS
ioctl, which can be called out-of-band and needs a separate lock).
Signed-off-by: Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx>
Acked-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/kvm/diag.c | 4 +---
arch/s390/kvm/interrupt.c | 3 +++
arch/s390/kvm/kvm-s390.c | 12 ++++++++++++
3 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
index 3a74d8a..78d967f 100644
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -107,14 +107,13 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
{
- int ret, idx;
+ int ret;
/* No virtio-ccw notification? Get out quickly. */
if (!vcpu->kvm->arch.css_support ||
(vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
return -EOPNOTSUPP;
- idx = srcu_read_lock(&vcpu->kvm->srcu);
/*
* The layout is as follows:
* - gpr 2 contains the subchannel id (passed as addr)
@@ -125,7 +124,6 @@ static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
vcpu->run->s.regs.gprs[2],
8, &vcpu->run->s.regs.gprs[3],
vcpu->run->s.regs.gprs[4]);
- srcu_read_unlock(&vcpu->kvm->srcu, idx);
/*
* Return cookie in gpr 2, but don't overwrite the register if the
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 7f35cb3..e7323cd 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -436,6 +436,7 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
hrtimer_start(&vcpu->arch.ckc_timer, ktime_set (0, sltime) , HRTIMER_MODE_REL);
VCPU_EVENT(vcpu, 5, "enabled wait via clock comparator: %llx ns", sltime);
no_timer:
+ srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
spin_lock(&vcpu->arch.local_int.float_int->lock);
spin_lock_bh(&vcpu->arch.local_int.lock);
add_wait_queue(&vcpu->wq, &wait);
@@ -455,6 +456,8 @@ no_timer:
remove_wait_queue(&vcpu->wq, &wait);
spin_unlock_bh(&vcpu->arch.local_int.lock);
spin_unlock(&vcpu->arch.local_int.float_int->lock);
+ vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+
hrtimer_try_to_cancel(&vcpu->arch.ckc_timer);
return 0;
}
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 8eec7ab..1e4e7b9 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -752,11 +752,18 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
{
int rc, exit_reason;
+ /*
+ * We try to hold kvm->srcu during most of vcpu_run (except when run-
+ * ning the guest), so that memslots (and other stuff) are protected
+ */
+ vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+
do {
rc = vcpu_pre_run(vcpu);
if (rc)
break;
+ srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
/*
* As PF_VCPU will be used in fault handler, between
* guest_enter and guest_exit should be no uaccess.
@@ -767,10 +774,12 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
exit_reason = sie64a(vcpu->arch.sie_block,
vcpu->run->s.regs.gprs);
kvm_guest_exit();
+ vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
rc = vcpu_post_run(vcpu, exit_reason);
} while (!signal_pending(current) && !rc);
+ srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
return rc;
}
@@ -968,6 +977,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
{
struct kvm_vcpu *vcpu = filp->private_data;
void __user *argp = (void __user *)arg;
+ int idx;
long r;
switch (ioctl) {
@@ -981,7 +991,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
break;
}
case KVM_S390_STORE_STATUS:
+ idx = srcu_read_lock(&vcpu->kvm->srcu);
r = kvm_s390_vcpu_store_status(vcpu, arg);
+ srcu_read_unlock(&vcpu->kvm->srcu, idx);
break;
case KVM_S390_SET_INITIAL_PSW: {
psw_t psw;
--
1.8.3.1
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